1. Field of the Invention
The present invention is directed to a welding hood which provides the welder with an extended line of sight capability. More particularly, the invention is concerned with a welding hood having a periscopic view piece, thereby allowing the wearer to view welding activity above the welder's unaided line of sight.
2. Description of the Prior Art
Welding hoods are commonly used to protect the welder's eyes against the brilliance of the welding arc or flame and against sparks and other debris that may be thrown off during the welding operation. Welder's in these circumstances are typically working with hand-held equipment on workpieces within their reach. Such welding hoods typically include a face mask supported by a head band or other mount for supporting the hood on the head of the welder. The face mask includes a view piece which is darkened by colored or filtering glass to shield the wearer's eyes from the brilliant light of the welding arc or flame. Such conventional welding hoods are satisfactory for many welding operations where the welder's head is unobstructed by the working environment and the welder has a direct line of sight through the viewpiece to the workpiece and welding area, but are very limiting in elevated or confined work areas.
Attempts to provide alternatives to the conventional welding hood have resulted in some modest improvements. U.S. Pat. No. 1,885,744 to Malcom shows a welding hood using a tiltable second mirror for directing the image to the wearer's eyes, thereby giving an improved view through the objective window positioned in the direct line of sight of the wearer, but does not extend the wearer's line of sight to view objects above the line of sight and in fact impedes viewing of elevated objects. U.S. Pat. No. 2,211,238 to Links shows a light filter which permits the transmission of harmless light rays and intercepts harmful rays by an arrangement of prisms, but does not enhance the welder's field of vision. U.S. Pat. No. 4,646,363 to Wood shows a welder's helmet which provides two objective lenses to permit direct line-of-sight viewing from the welder's eyes to objects straight ahead and below the hood, but does not enhance the welder's field of vision to a displaced location outside the wearer's direct line of sight. U.S. Pat. No. 5,331,473 to Petersen shows a viewing system used with welding hoods where the objective window is slightly angled downwardly to prevent reflections, but does not enhance the welder's field of vision to enable viewing beyond his ordinary line-of-sight. U.S. Pat. No. 5,398,341 to Trapple provides a hinged objective lens to permit clear, unshielded vision and then a darkened lens where the welder can shift the darkened lens into position without the use of hands, but does not enhance the wearer's line of sight.
There has thus developed a need for an improved welding hood which extends the welder's field of vision above the unaided line of sight and permits viewing over or around obstacles during welding. There has further developed a need for a welding hood which provides a displaced objective window outside and preferably above the welder's usual line of sight, whereby the welder may view the work within reach but blocked from direct viewing by the bulk of the protective mask. There is an additional need for a welding hood which permits the wearer to control the displacement of the objective window relative to his ordinary line of sight to permit optimum viewing of the workpiece within his reach while retaining the convenience and protection of a head-mounted welding hood. Finally, there is a need for an improved welding hood where the wearer may adjust the angle of the view received by a reflecting member so as to provide and enlarged field of view through the displaced objective window.